Transmission



April 3, 1945.

P. ORR 2,312,734 TRANSMISSION 4/ 7 2 Sheets-Sheet 1 Filed July 8, 1943azfnz/en' ar'" P mer Orr Examiner UNITED STATES PATENT OFFICETRANSMISSION Palmer Orr, Muncie, Ind., assignor to Borg-WarnerCorporation, Chicago, 111., a corporation of Illinois Application July8, 1943, Serial No. 493,827

17 Claims.

This invention relates to transmissions and more particularly totransmissions which are suitable for use in airplanes between theengines and propellers thereof and function to drive the propellers atlower than engine speed.

In a co-pending application of William E. Moffitt, Serial No. 359,987,filed October 7, 1940, there is disclosed an airplane transmissinproviding two speed ratios, an underdrive speed ratio and a directdrive. The direct drive is provided by means of a dog interengaging in awindow or slot provided in another element, and the underdrive speedratio is provided by means of gearing and braking means providing areaction point for the gearing. The braking means comprises a onewayroller brake and a friction brake, with the construction being such thatthe one-way brake takes the greater part of the reaction for driving apropeller on the driven shaft of the transmission through thetransmission and the friction brake takes the reaction when thepropeller tends to drive the driving shaft of the transmission and anairplane engine connected therewith and functions as a flywheel for theengine. The dog may be shifted in and out of engagement with thecorresponding window, and the friction brake may be engaged anddisengaged for changing the speed ratio of the transmission.

It is an object of my invention to provide an improved transmissionparticularly suitable for airplanes which is of such construction thatthe input and output shafts are not disconnected at any speed ratio atwhich the transmission may be set whereby a propeller on the drivenshaft of the transmission may always function as a flywheel for anengine connected with the driving shaft and which is of suchconstruction that the shift from one speed ratio to another may be madeby actuating a single operator, such as a coupling unit or moreparticularly a positive type brake, as distinguished from the twooperators, the friction brake and dog, required to be actuated forshifting the Moffltt transmission.

It is another object of my invention to provide an improved transmissionof this type for driving at a low or high speed ratio having a positivecoupling unit, particularly in the form of a positive brake havinginterengageable elements, which provides the high speed ratio throughthe transmission when engaged and to provide a construction forpreventing the lnterengageable elements of the coupling unit fromcontacting each other when there is relative rotation between theinterengageable elements and allowing the elements to engage when thereis substanital synchronism between the elements. To this end it is anobject to provide a one-way brake for taking the coast load through thetransmission, that is, a load due to the driven shaft of thetransmission driving the driving shaft of the transmission, a blockermember for normally blocking engagement of the positive coupling unit,and a spring construction permitting the elements of the one way braketo have a limited relative movement in the direction for engaging theone-way brake and with the elements on such movement moving the blockermember whereby it allows engagement of the positive coupling unit.

In its preferred form my improved transmission comprises a drivingshaft, a driven shaft, a planetary underdrive gear set for driving thedriven shaft, a one-way clutch for connecting the driving shaft with theunderdrive gear set for providing a low speed ratio, a planetaryoverdrive gear set for selectively driving the underdrive gear set, withthe overdrive gear set comprising ring, sun and planet gears and aplanet gear carrier which is driven by the driving shaft, apositive-type brake for the sun gear of the overdrive gear set andcomprising a slotted element on the sun gear and a plunger for engagingthe slotted element and providing a high speed ratio between the drivingand driven shafts when engaged, a one-way brake for the sun gear of theoverdrive unit whereby the driving shaft may drive the driven shaft in aforward direction through the overdrive gear set and whereby the slottedelement may be stopp d from rotation, a spring means in series with theone-way brake for allowing a limited rotation of the sun gear of theoverdrive unit in a direction reverse to its rotation when the drivenshaft is being driven at low speed ratio, and a blocker element forblocking engagement of the plunger with the slotted element when the sungear of the overdrive unit is rotating due to the driven shaft beingdriven at low speed ratio and with the blocker being actuated on thelimited rotation of the sun gear in the reverse direction for thereafterpermitting engagement of the plunger with the slotted element. It iscontemplated that the overdrive gear set shall preferably be such as tocause an increase in speed which is less than the decrease in speedcaused by the underdrive gear set whereby the driven shaft at eitherspeed ratio rotates at less speed than the driving shaft.

My invention consists of the novel constructions, arrangements anddevices to be hereinafter described and claimed for carrying out theabovestated objects and such other objects as will ap pear fromthe'following description of a certain preferred embodiment illustratedin the accompanying drawings, wherein:

Fig. 1 is a longitudinal sectional view of a transmission embodying theprinciples of my invention;

Fig. 2 is a sectional view taken on line 22 of Fig. 1;

Fig. 3 is a sectional view taken on line 3--3 of Fig. l; and

Fig. 4 is a sectional view taken on line 4-4 of Fig. 1.

Like characters of reference designate like parts in the several views.

The illustrated transmission comprises a driving shaft I8 and a drivenshaft II, with the shaft II being rotatably mounted with respect to atransmission housing I2 by means of a bearing I3 of the ball type andbeing journaled inside the shaft I8 as shown. The shaft I8 is adapted tobe connected with an airplane engine (not shown) and to be driventhereby, and the shaft II is adapted to carry an airplane propeller (notshown) and to drive the propeller.

An underdrive unit I4 is provided which is adapted to be driven by thedriving shaft I8 and to drive the driven shaft I I. The underdrive unitl4 comprises a sun gear I5 which is fixed with respect to thetransmission housing I2 by means of bolts I8 as shown, a ring gear IT, aplurality of planet gears I8 (one being shown in the drawings) in meshwith the sun gear I5 and a portion I'la of the ring gear I], a pluralityof stub shafts I9 each of which carries one of the gears I8, and aplanet gear carrier element 28 carrying the shafts I9 and splined to theshaft II. 1

The driving shaft I8 is connected to drive the underdrive unit I4 bymeans of a one-way roller clutch 2 I. The clutch 2| comprises aplurality of rollers 22, an inner cylindrical urface 23 formed on amember 24 and cammed surfaces 25 formed on an inner member 25.Spring-pressed plungers 21 are provided for wedging the rollers 22between the surfaces 25 and 23, and the clutch 2I engages when themember 26 is rotated in the counterclockwise direction, as seen in Fig.4, with respect to the member 24 and disengages when the members 24 and26 move in the reverse directions with respect to each other as isapparent. The member 28 is splined to the shaft I8, and the member 24 issplined to the ring gear I], and the members 28 and 24 thereby rotatewith the shaft I8 and ring gear I! respectively. When the shaft I8 isrotated in a foward direction as indicated by the arrow in Fig. l, themember 26 is rotated in such direction or counterclockwise as seen inFig. 4, and the roller clutch 2| is engaged to rotate the member 24, andring gear II also in such direction. Such movement of the ring gear IIrevolves the planet gears I8 about the sun gear I5, and the carrierelement 28 and shaft II are thereby also rotated in the same directionas shaft I8 but at a slower speed or reduction speed ratio, as isapparent.

A planetary overdrive unit 28 is provided for selectively driving theunderdrive unit I4 instead of allowing the unit I4 to be driven by meansof the roller clutch 2 I, to provide another speed ratio. The overdriveunit 28 comprises a sun gear 29 rotatively disposed on the shaft I8. thering gear I1, a plurality of planet gears 38 (one being shown in thedrawings) which are in mesh with the sun gear 29 and the portion I'lb ofthe ring gear I], a plurality of stub shafts 3I each of which carriesone of the gears 38, and a flange portion 32 on the shaft I8 carryingthe stub shafts 3| and functioning as a planet gear carrier.

Positive-type means for coupling the sun gear 29 to the housing I2 orbraking the sun gear is provided whereby the overdrive unit 28 may bemade effective to drive the underdrive unit I4. The braking meanscomprises an element 33 splined to the sun gear 29 and provided withslots 34, and a plunger 35 slidably disposed in a suitable cavity in atransmission housing portion I2a and adapted to engage in any of theslots 34 in the element 33. A spring 38 is provided for urging theplunger 35 into engagement in any of the slots 34, and the plunger isprovided with a shank 31 by means of which the plunger may be manuallyoperated to disengage the plunger from the slotted element 33. Theoverdrive unit 28, as is apparent, is effective to drive the underdriveunit I4 through the ring gear II when the plunger 35 is in engagementwith any of the slots 34, and the overdrive unit 28 is ineffective todrive the unit I4 whereby the latter unit may be driven through theroller clutch 2| when the plunger 35 is out of engagement in any of theslots 34. The plunger 35 when in engagement in any of the slots 34functions to hold the element 33 and thereby the sun gear 29 againstrotation in either direction, and thus the drive through the overdriveunit and thereby between the shafts I8 and II is a two-way drive wherebythe shaft I8 may drive the shaft I I or vice versa.

Auxiliary one-way means for coupling the sun gear 29 to the housing I2or braking the sun gear is also provided, in addition to the positivebraking means including the plunger 35 and slotted element 33. Theone-way braking means comprises a roller unit 38 and spring means 39 inseries with the roller unit. The .unit 38 is formed by a member 48splined to the sun gear 29, an annular element 4I disposed about theelement 48 and rollers 42 between the elements 48 and 4I. The element 48is provided with cammed surfaces 43, and the element 4I is provided witha cylindrical surface 44, and spring pressed plungers 45 are providedfor acting on the rollers 42 to wedge the rollers between the surfaces43 and 44, whereby the unit 38 functions when the element 48 tends torotate in a clockwise direction as seen in Fig. 2 to connect theelements 48 and M, as is apparent.

The sprin means 39 in series with the unit 38 comprises a. pair of discs46 and 41 on opposite sides of the element M. The discs fit in a tubularportion 48 provided on the transmission housing portion I2a, and each ofthe .discs is provided with lug portions 49 which fit in appropriateslots provided in the tubular portion 48 and function to hold the discsagainst rotation. The element M is provided with a plurality of slots 58in its periphery in each of which is disposed a spring 5I, and the discs46 and 41 are provided with slots 52 and 53 respectively which are ofsubstantially the same length as the slots 50 and which receive sideportions of the springs 5|, as shown. The spring means 39 functions toallow a limited movement of the element H in a clockwise direction asseen in Fig. 2- with the slots 58 each bearing on one end of a spring 5|and with ends of slots 52 and 53 corresponding to the 'slot 58 bearingon the opposite end of the spring and with the spring being therebycompressed by such movement of the element 4I. Such movement of element4I may be under the action of the roller unit 38, after the unitmata=aew blocker as seen in Fig. 3, and the abutment 56 being adapted tocontact a part of the housing portion I20. and prevent furthercounterclockwise movement of the blocker 54. The blocker 54 is alsoprovided with a blocking surface 51 which, when the plunger 35 is movedupwardly from its position as seen in the drawings and when the blocker54 is rotated in a counterclockwise direction from its position as seenin the drawings such that the abutment 56 contacts the housing portionI2a, functions to prevent movement of the plunger downwardly forengaging in any of the slots 34.

The illustrated transmission provides two forward speed ratios, a lowspeed ratio and a high speed ratio. .The drive in low speed ratio isthrough the one-way clutch 2I and the underdrive unit I4, and the drivein high speed ratio is through both of the units 28 and I4. It will beobserved that the planet gears 30 are larger in size than the planetgears l8, and since the units 28 and I4 utilize different portions ofthe same ring gear II, the decrease in speed ratio provided by the unitI4 is greater than the increase in speed ratio provided by the unit 28when the latter is efiective. The high speed ratio utilizing the unit28, as well as the low speed ratio utilizing the unit I4 only, aretherefore underdrive ratios; that is to say, the driven shaft II at bothspeed ratios is rotating at a slower speed than the shaft I0,

When the plunger 35 is retracted by the operator against the action ofthe spring 36 and is disengaged from the slotted element 33, the unit 23is ineffective and the shaft II is driven at low speed ratio. The drivein low speed ratio is from the shaft I through the element 26, therollers 22, the element 24, the ring gear H, the gears I3, the stubshafts I9 and the element 20 t0 the shaft II. The ring gear I1 is drivenat the same speed as the shaft In by means of the clutch 2|, and sincethe sun gear I5 is stationary, the element 20 and thereby the shaft IIare rotated at a certain underdrive low speed ratio with respect toshaft III, as is apparent. At this ratio, the sun gear 29 rotatescounterclockwise as seen in Fig. 3 at the same speed and in the samedirection as the shaft I0 since the ring gear I! and carrier portion 32are both rotating forwardly at the same speed, and the blocker 54 isrotated counterclockwise due to its frictional contact with the element33 until the abutment 56 contacts the housing portion I2a to preventfurther such rotation of the blocker, and the surface 51 becomespositioned under the plunger 35 to prevent its downward movement forengaging in any of the slots 34 if the shank 31 is released by theoperator for allowing the spring 35 to be effective to move the plungerdownwardly.

The transmission provides high speed ratio when the plunger 35 isengaged in one of the slots 34 in the element 33 thereby holding theExaminer element 33 and the sun gear 29 stationary. The drive is thenfrom the shaft III through the flange portion 32, the stub shafts 3|,the planet gears 30, to the ring gear II, with the gears 29, and I1acting as an overdrive to drive the gear H at a greater speed than theshaft I0, and the drive from the ring gear I! is through the planetgears I8, the stub shafts I9, the carrier portion 20 to the shaft II,with the ring gear II, the planet gears I8 and the sun gear I5functioning as an underdrive. When the shaft II is thus driven, sincethe ring gear I1 is rotating at a faster speed than the shaft ID, theone-way clutch 2I overruns and thereby breaks the connection madethrough the clutch between the ring gear I! and the shaft II) for thedrive in low speed ratio.

The roller units 2I and 38 are so arranged as to provide a two-wayconnection between the shafts I0 and II, that is, a connection wherebythe shaft III may drive the shaft I I or vice versa, when the plunger isdisengaged from the slotted element 33 and the transmission is set forlow speed drive. The plunger 35 is so arranged to engage with the slots34 in the member 33 so as to prevent a rotation of the member 33 ineither direction, as has been hereinbefore explained, and it will thusbe apparent that in high speed drive, the drive is two-way, that is,either shaft may drive the other. In low speed drive, however, as hasbeen explained, the drive is through the one-way clutch 2| which maydisengage and permit the ring gear H to rotate at a faster speed thanthe shaft III whereby the connection between the shafts through the lowspeed power train is broken. When the transmission is set for low speeddrive and the shaft II tends to rotate at a higher speed than that atwhich it is driven through the clutch 2|, the ring gear I! and shaft IIwill rotate free of shaft I0 until the speed of the ring gear I! hasincreased such that its speed ratio with respect to the shaft I0 is thatwhich would be provided by the overdrive unit if it were effective. Atthis speed of the gear H, the sun gear 29 will have stopped its rotationin a counterclockwise direction as seen in Figs. 2 and 3, and anyfurther increase in speed of the gear I1 with respect to the shaft Illwill be prevented by the one-way brake comprising roller unit 38 andspring means 39 becoming effective to prevent a rotation of the sun gear29 in a clockwise direction as seen in these figures. The one-way brakethus functions to complete a power train through the overdrive unit 28whereby the driven shaft I I may rotate the driving shaft I0, and apropeller on shaft II when rotating may thus function as a flywheel forrotating shaft I0 and an engin connected with the latter shaft. If anengine connected with the shaft I0 is brought to idling speed, theengine will not stall due to the lack of a flywheel, due to thisfunction of the one-way brake.

When the shaft I I is being driven in low speed drive through theone-way clutch 2|; the sun gear 29, as has been hereinbefore explained,is rotating in a counterclockwise direction as seen in Figs. 2 and 3.With the plunger 35 having been moved upwardly out of position forengaging in any of the slots 34 by means of the shank 31, such rotationof the sun gear 29 and thereby the element 33 acts to move the blocker54 and hold the blocker in a position with the abutment 56 in engagementwith the housing portion I2a. When the shank 31 is thereafter released,the surface 51 functions to hold the plunger 35 in a position whereby itmay not engage with the element 33, and the transmission is thusmaintained in low speed ratio. In order thereafter to shift thetransmission to provide high speed ratio, the speed of the shaft I isdecreased with respect to the speed of the shaft l with overrunning ofthe clutch 2| until the ratio of speeds between the shafts I0 and H issubstantially high speed ratio whereby the rotationof the sun gear 29 isstopped, the unit 38 is engaged, and the shaft drives the shaft I 0through the overdrive unit 28. The reaction point for the overdrive unit28, when the shaft H1 is thus being driven by the shaft through theoverdrive unit, is the one-way brake comprising unit 38, as is apparent,and the sun gear 29 has force applied thereto by the planet gears 30tending to rotate the sun gear in a clockwise direction as seen in Figs.2 and 3. This force applied to the sun gear 29 is transmitted throughthe unit 38 to the member 4|, and the member 4| rotates slightly in aclockwise direction as seen in Fig. 2 against the action of the springs5|, with the discs 46 and 41 remaining stationary due to theirprojections 49 disposed in slots in the tubular housing portion 48. Theunit 38, the element 40, the sun gear 29 and thereby the element 33rotate with the element 4| against the action of the springs 5| in aclockwise direction as seen in Fig. 2, and such rotation of the element33, due to the frictional contact between the blocker 54 and element 33functions to move the blocker clockwise as seen in Fig. 3 to move thesurface 51 to the right as seen in Fig. 3 from under the plunger 35, andthe plunger moves downwardly under the action of the spring 36 to aposition for engaging in any of the slots 34. The plunger will thenengage in one of the slots 34, with such engagement being without anyfurther rotation of the element 33 if a slot 34 is directly below theplunger when the plunger descends, or with a further rotation of theelement 33 against the action of the spring means 39, or when theelement 33 starts rotation in a counterclockwise direction as seen inFigs. 2 and 3 on the speed of the shaft l0 being increased after theplunger 35 has descended. In brief, then, a change of speed ratio fromlow speed ratio to high speed ratio is made by releasing the shank 31,whereby the spring 36 urges the plunger 35 against the surface 51, andthereafter decreasing the speed of the shaft I9, as by decelerating anengine connected with the shaft l9, whereby the shaft I may drive theshaft I0 and the sun gear 29 may change its direction of rotation fromcounterclockwise as seen in Figs. 2 and 3 to clockwise against theaction of the springs 5|, whereby the blocker 54 is rotated out ofblocking position to allow the plunger 35 to move downwardly intoposition for engaging any of the slots 34, and then applying torque toshaft H) for driving shaft H.

In order to shift the transmission from high speed ratio to low speedratio, the plunger 35 is withdrawn from the slot 3'4, in which it wasengaged for high speed ratio, against the action of the spring 36. Thering gear I! is then again driven through the one-way clutch 2|, and theshaft H is driven at low speed ratio. The sun gs ar 29 again rotates ina counterclockwise direction as seen in Figs. 2 and 3 to disengage theunit 38 and to move the blocker 54 counterclockwise as seen in Fig. 3whereby its abutment 56 contacts the housing portion I24; and thesurface 51 is positioned beneath the plunger 35 whereby the plunger ifreleased may not move downwardly into position for engaging in any ofthe slots 34.

My improved transmission is of such construction that it may be easilycontrolled; it is only necessary to disengage the plunger 35 from theelement 33 to shift to low speed ratio from high speed ratio and torelease the plunger 35 whereby the spring 36 may freely act on theplunger and to decrease the speed of the shaft III with respect to theshaft II for shifting from low speed ratio to high speed ratio. Thetransmission further is of such construction that in either low or highspeed ratio, either of the shafts ID or II may drive the other shaft.Due to the provision of the one-way brake, including roller unit 38 andspring means 39. and the blocker 54, there is no unnecessary andprobably harmful ratcheting of the plunger 35 on the slotted element 33prior to engagement of the plunger and slotted element.

I wish it to be understood that I do not intend to limit my invention tothe constructions and arrangements shown and described except onlyinsofar as certain of the appended claims are specifically so limited,as it will be apparent to those skilled in the art that modificationsmay be made without departing from the principles of the invention.

I claim:

1. In a transmission, the combination of a driving shaft, a drivenshaft, means providing a power train between said shafts and includinga. positive coupling for connecting a certaintwo elements together andthereby completing the power train, said coupling comprising a pair ofinterengageable members, said members ratcheting over each other if theyare in contact but out of interengagement and there is relative movementbetween said elements, a one-way coupling between said two elements forcompletin said power train when said positive coupling is disengaged,yieldable means between one of said elements and said one-way couplingfor allowing a limited movement of one of said elements with respect tothe other element in the direction for engaging the one-way couplingafter the one-way coupling is engaged, and a movable obstruction forallowing and preventing engagement of said interengageable members, saidobstruction being actuated by relative movement between said elementswhereby to prevent contact between said interengageable members andthereby to prevent ratcheting of the members on each other when saidelements move with respect to each other such that the one-way couplingoverruns and being moved out of the way of said interengageable membersto allow interengagement thereof when there is a reversal of movementbetween said elements with engagement of the one-way coupling andstressing of said yieldable means.

2. In a transmission, the combination of a driv ing shaft, a drivenshaft, means providing a power train between said shafts and including apositive coupling for connecting a certain two elements together andthereby completing the power train, a one-way coupling between said twoelements for completing said power train when the positive coupling isdisengaged, yieldable means between one of said elements and saidc-ne-way coupling for allowing a limited movement of one of saidelements with respect to the other element in the direction for engagingthe one-way coupling after the one-way coupling is engaged, and ablocker member actuated by relative movement between said elements forpreventing engagement of said positive coupling when said elements movewith respect to each other such that the one-way coupling overruns andpermitting engagement of the positive coupling when there is a reversalof movement between said elements with a stressing of said yieldablemeans.

3. In a transmission, the combination of a driving shaft, a drivenshaft, means providing a power train between said shafts for rotatingsaid driven shaft at a low speed ratio with respect to said drivingshaft, automatic means for breaking said power train, means providinganother power train between said shafts for rotating said driven shaftat a higher speed ratio with respect to said driving shaft, said lastnamed means including positive coupling means for completing saidlast-named power train, one-way coupling means for coupling two elementstogether for thereby completing said last-named power train when saidpositive coupling means is disengaged, yieldable means connectedserially with said, oneway coupling means for allowing a limitedmovement of one of said elements with respect to the other element inthe direction for engaging the one-way coupling means after the onewaycoupling means is engaged, and means for engaging said positive couplingmeans on such relative movement between said elements.

4. In a transmission, the combination of a driving shaft, a drivenshaft, means providing a power train between said shafts for rotatingsaid driven shaft at a low speed ratio with respect to said drivingshaft and including a oneway clutch, means providing another power trainbetween said shafts for rotating said driven shaft at a higher speedratio with respect to said driving shaft, said last named meansincluding a positive coupling for completing said last-named powertrain, a one-way coupling for coupling a certain two elements togetherfor thereby completin: said last named power train when the pcsitivecoupling is disengaged, spring means connected serially with saidone-way coupling for allowing a limited movement of one of said elementswith respect to the other element in the direction for engaging theone-Way coupling after the one-way coupling is en aged, and a blockermember actuated by relative movement between said elements whereby toprevent engagement of said positive couplin when said elements move withrespect to each other such that the one-way coupling overruns and topermit engagement of the positive coupling when the"e is a reversal ofmovement between said ehments with a stressin of said spring means.

5. In a transmission. the comb nation of a driving shaft, a drivenshaft. gearing providing a power tra n between said shafts and includinga positive brake for an element of the gearing for completing the powertrain. a one-way brake for raid element for complet ng the power trainwhen the pos'tive brake is disengaged, yieldable means connectedserially with said one-way brake for allow ng a limited movement of saidelement in the direction for engaging the one-way brake after theone-way brake is engaged, and a blocker actuated by movement of saidelement whereby to prevent engagement of said positive brake when saidelement moves in a directon such that the one-way brake overruns and toallow engagement of the positive brake when there is a reversal ofmovement of said element with a stressing of said yieldable means.

training? 6. In a transmission, the combination of a driv ing shaft, adriven shaft, gearing providing a power train between said shafts forrotating said driven shaft at a certain speed ratio with respect to saiddriving shaft, a one-way clutch for said gearing adapted forautomatically breaking said power train, gearing providing another powertrain between said shafts for rotating said driven shaft at a higherspeed ratio with respect to said driving shaft, said last-named gearingincluding a positive type brake for an element of the gearing forcompleting said last-named power train, a one-way brake for said elementfor completing said last-named power train when the positive brake isdisengaged and overrunning when said dn'ven shaft is driven through saidfirst-named power train, yieldable means connected serially with saidone-way brake for allowing a limited movement of said element in thedirection for engaging the one-way brake after the latter brake isengaged, and a blocker actuated by movement of said element forpreventing engagement of said positive brake when said element moves ina direction such that the one-way brake overruns and allowing engagementof the positive brake when there is a reversal of movement of theelement with a stressing of said yieldable means.

7. In a transmission, the combination of a driving shaft, a drivenshaft, gearing providing a power train between said shafts for rotatingsaid driven shaft at a certain speed ratio with respect to said drivingshaft, a one-way clutch for completing said power train and adapted tooverrun to break said power train, gearing providing another power trainbetween said shafts for rotating said driven shaft at a higher speedratio with respect to said driving shaft, a positive brake for anelement of said last-named gearing and functioning to complete saidlast-named power train, said brake comprisin a pair of interengageablemembers and spring means for urging said members into engagement, saidmembers ratcheting over each other if they are in contact but out ofengagement and there is movement of said element, a one-way brake forsaid element for completing said last-named power train whereby saiddriven shaft may drive said driving shaft and overrunning when saiddriven shaft is driven through said first-named power train, yieldablemeans connected serially with said one-way brake for allowing a limitedmovement of said element in the direction for engaging the one-way brakeafter the one-way brake is engaged, and a movable obstruction forallowing and preventing engagement of said interengageable members, saidobstruction being actuated by movement of said element whereby toprevent contact between said members and thereby to prevent ratchetingof the members on each other when the drive is through said first-namedpower train and said element moves such that the one-way brake overrunsand whereby to be moved out of the way of said interengageable membersto allow interengagement thereof when there is a reversal of movement ofsaid element with engagement of the one-way brake and stressing of saidyieldable means due to the driving of said driving shaft by said drivenshaft through said second-named gearing.

8. In a transmission, the combination of a driving shaft, a drivenshaft, planetary gearing comprising a. sun gear element, a ring gearelement, a planet gear in mesh with said sun and ring gear elements anda planet gear carrier element, one of said elements being connected indriving relation with one of said shafts and another of said elementsbeing connected in driving relation with the other of said shafts, apositive brake and a one-way brake for the other of said elements. andyieldable means associated with said one-way brake for allowing rotationof said last-named element in the direction for engaging said onewaybrake, and means for engaging said positive brake on rotation of saidlast-named element in the direction for engaging the one-way brake.

9. In a transmission, the combination of a driving shaft, a drivenshaft, planetary gearing comprising a sun gear element, a ring gearelement, a planet gear in mesh with said ring gear and sun gearelements, and a planet gear carrier element, one of said elements beingconnected in driving relation with one of said shafts and another ofsaid elements being connected in driving relation with the other of saidshafts, a positive brake and a one-way brake for the other of saidelements, yieldable means associated with said one-brake for permittingmovement of said last-named element in the direction for engaging theone-way brake, and a blocker for preventing engagement of said positivebrake when said last-named element moves in a direction such that theone-way brake overruns and actuated by a reversal of movement of saidlast-named element with an engagement of the one-way brake and astressing of said yieldable means for permitting engagement of thepositive brake.

10. In a transmission, the combination of a driving shaft, a drivenshaft, planetary gearing comprising a sun gear, a ring gear, a planetgear in mesh with the sun and ring gears, and a planet gear carrier,said ring gear being connected in driving relation with said drivenshaft and said carrier being connected in driving relation with saiddrivng shaft, a positive brake and a one-way brake for said sun gear,said positive brake comprising a slotted element connected with the sungear and a plunger for engaging the slotted element, yieldable meansconnected serially with said one-way brake for permitting restrictedrotation of the sun gear in the direction for engaging the one-waybrake, and a blocker element actuated by movement of said sun gear andslotted element whereby to prevent engagement of said plunger andslotted element when said sun gear rotates in the direction such thatthe one-way brake overruns and allowing engagement of the plunger withthe slotted element when there is a reversal of rotation of said sungear with a stressing of said yieldable means.

11. In a transmission, the combination of a driving shaft, a drivenshaft, means providing a power train between said shafts for rotatingsaid driven shaft at a certain speed ratio with respect to said drivingshaft and including a one-way clutch, means pro iding another powertrain between said shafts for rotating said driven shaft at a higherspeed :atio with respect to said driving shaft, said last-named meansincluding planetary gearing comprising a ring gear adapted to drive saiddriven shaft, a sun gear, a planet gear in mesh with the sun and ringgears, and a planet gear carrier adapted to be driven by said drivingshaft, a positive brake for said sun gear, a oneway brake for said sungear whereby said driven shaft may drive said driving shaft through saidsecond-named power train, spring means associated with said one-waybrake for permittin movement of said sun gear in a direction forengaging the one-way brake after the one-way brake is engaged, and ablocker element actuated by movement of said sun gear and preventingengagement of said positive brake when said sun gear rotates in adirection such that the one-way brake overruns and permitting engagementof the positive brake when there is a reversal of rotation of the sungear with a, stressing of said yieldable means.

12. In a transmission, the combination of a driving shaft, a drivenshaft, a planetary underdrive unit connected to drive said driven shaft,a one-way clutch for connecting said driving shaft and said underdriveunit, a planetary overdrive unit driven by said driving shaft andadapted for selectively driving said underdrive unit, a positive brakefor the sun gear of said overdrive unit for making the overdrive uniteffective for driving said underdrive unit. and a one-way brake for saidsun gear whereby said driven shaft may drive the driving shaft throughsaid two units.

13. In a transmission, the combination of a driving shaft, a drivenshaft, a planetary underdrive unit connected to drive said driven shaft,a one-way clutch for connecting said driving shaft and said underdriveunit, a planetary overdrive unit driven by said driving shaft andadapted for selectively driving said underdrive unit, a positive brakefor the sun gear of said overdrive unit for making the latter uniteffective for driving said underdrive unit, a one-way brake for said sungear whereby said driven shaft may drive the driving shaft through saidoverdrive unit, yieldable means associated with said one-way brake forpermitting said sun gear to rotate in a direction for engaging saidone-way brake after the one-way brake is engaged, and means for engagingsaid positive brake on such rotation of said sun gear against saidyieldable means.

14. In a transmission, the combination of a driving shaft, a drivenshaft, a planetary underdrive unit connected to drive said driven shaft,a one-way clutch for connecting said driving shaft and said underdriveunit, a planetary overdrive unit driven by said driving shaft andadapted for selectively driving said underdrive unit, a positive brakefor the sun gear of said overdrive unit for making the overdrive uniteffective, a one-way brake for said gear whereby said driven shaft maydrive said driving shaft through said overdrive unit, yieldable meansassociated with said one-way brake whereby said sun gear may rotate inthe direction for engaging the oneway brake after the one-way brake isengaged, and a blocker element actuated by rotation of said sun gear forpreventing engagement of said positive brake when said sun gear rotatesin the direction such that the one-way brake overruns and permittingengagement of the positive brake when there is a reversal of rotation ofsaid sun gear with a stressing of said yieldable means.

15. In a transmission, the combination of a driving shaft, a drivenshaft, an underdrive unit for driving said driven shaft and comprising astationary sun gear, a ring gear, a planet gear in mesh with the sun andring gears, and a planet gear carrier connected with said driven shaft,a one-way roller clutch connected between said ring gear and saiddriving shaft whereby said driving shaft may drive said underdrive unit,a planetary overdrive unit driven by said driving shaft and adapted forselectively driving said underdrive unit, said overdrive unit comprisinga ring gear connected with said first-named rin gear, a sun gear, aplanet gear in mesh with the sun and ring gears of the overdrive unit,and a carrier for the planet gear of the overdrive unit and connectedwith said driving shaft, a positive brake for the sun gear of saidoverdrive unit for making the overdrive unit effective and comprising aslotted element rotatable with the sun gear of the overdrive unit and aplunger adapted to engage with the slotted element, said underdrive unitbeing so arranged as to provide a greater decrease of speed ratio fromits ring gear to its driven shaft than the increase of speed ratioprovided by said overdrive unit between said driving shaft and the ringgear of the overdrive unit, a one-way roller brake for the sun gear ofsaid overdrive unit and comprising a roller clutch unit and a stationaryelement, spring means between said roller clutch unit and saidstationary element whereby the sun gear may rotate in the direction forengaging the one-way brake after the one-way brake is engaged, a blockerelement actuated by rotation of the slotted element and sun gear of theoverdrive unit and preventing the engagement of said plunger with theslotted element when the sun gear rotates in the direction such that theone-way brake overruns and allowing engagement of the plunger with theslotted element when there is a reversal of rotation of the sun gear ofthe overdrive unit with a stressing of said spring means, spring meansfor urging said plunger into engagement with said slotted element, andmanually operated means for disengaging the plunger from the slottedelement.

16. In combination, two relatively rotatable elements, a positivecoupling for coupling said elements together, a one-way coupling torcou- Examiner pling the elements together, blocker means actuated byrelative rotation between said elements for preventing engagement ofsaid positive coupling when there is relative rotation between saidelements in the direction such that the oneway coupling overruns andallowing engagement of the positive coupling When there is relativerotation in the opposite direction between said elements, and yieldablemeans connected between said one-Way coupling and one of said elementsfor allowing relative rotation between the elements after the one-waycoupling is engaged in the direction for engaging the one-way coupling.

17. In combination, a stationary element and a rotatable element, apositive brake for said rotatable element and comprising a membermovable with the rotatable element and a second member interengageabletherewith and held against rotation by said stationary element, aone-way brake for said rotatable element and comprising a member movablewith the rotatable element and a member held against rotation by saidstationary element, a. blocker member actuated by movement of saidrotatable element and preventing engagement of said positive brake whenthe rotatable element rotates in the direction such that the one-waybrake overruns and allowing engagement of the positive brake when thereis a, reversal of rotation of said rotatable element, and spring meansoperatively disposed between one of said elements and said one-way brakefor allowing a restricted rotation of said rotatable element after theone-way brake is engaged in the direction for engaging the one-waybrake.

PALMER ORR.

